A novel approach to improving the electromechanical properties of PZT-based piezoelectric ceramics via a grain coating modification strategy

In the present work, we used a hybrid ceramic fabrication technology to synthesize lead zirconate titanate (PZT) piezoelectric ceramics coated with yttrium oxide?stabilized zirconia (YSZ) powders (PZT@YSZ). The tailoring effects of the YSZ grain coating layer were investigated systematically. The results demonstrate that the mechanical properties of the modified PZT ceramics were successfully improved, which is mainly attributed to the synergistic effect of reinforced martensitic transformation toughening, micro-crack toughening, and secondphase dispersion toughening of the YSZ grain coating layer. More importantly, the piezoelectric properties of the PZT@YSZ ceramics, such as d33, kp, strain (S), strain hysteresis Hs, and d33*, have no declined, instead, have improved significantly. This is due to the coexistence of the rhombohedral-tetragonal phase of PZT in the PZT@YSZ ceramics, which is confirmed by Rietveld refinements in X-ray diffraction. Furthermore, the breakdown strength of the PZT@YSZ ceramics increased by 28%, a result of the reduction in grain size. This work describes an effective approach to simultaneously toughening PZT-based piezoelectric ceramics and enhancing their piezoelectric properties.